A plate or container (preferably white)
Skittles (other coated sweets work too)
Place your skittles on to the plate, try to alternate the colours.
Carefully pour water into the container, if the skittles move, just push them back into place quickly.
Watch what happens...
Skittles are coated in food colouring and sugar. When you pour water over the skittles the coloured coating dissolves spreading through the water.
The colour and sugar dissolve into the water and then diffuse through the water, making it the colour of the skittle.
Why do you think the colours don’t mix?
Can you spot the ‘S’ from the skittles? What happens to it?
How could you speed up the reaction?